[Study on the inhibition of testicular polyadenylate polymerase stimulated by manganese]

Many different types of naturally occurring substances and of drugs were examined as potential inhibitors of a Mn++-stimulated and poly(A)-primed polyadenylate polymerase that was partially purified from rat testis. By far the most active inhibitors were anionic dyes that were either of the diazo naphthyl sulfonate category, such as Evans Blue, or were halogenated derivatives of fluorescein, like Rose Bengal. The characteristics of these in vitro inhibitions, which did not involve any photo-sensitized reactions, were examined in considerable detail.